Socket for series lamps and string thereof



NOW 1951 c. M. RlVELY EI'AL SOCKET FOR SERIES LAMPS AND STRING THEREOFFiled May 17, 1947 Patented Nov. 27, 1951 UNITED STATES PATENT OFFICESOCKET FOR SERIES LAMPS AND STRING THEREOF Application May 17, 1947,Serial No. 748,776

2 Claims. I

This invention relates to a socket for series lamps and, moreparticularly, to one which will allow the remainder of the lamps in astring to keep burning if one, or a substantial proportion of the lamps,in said string burn out or are removed.

The principal object of our invention, generally considered, is toproduce a socket for lamps adapted to operate in series, as in a stringof Christmas tree or other lamps, said socket containing materialbridging the space between leads from lamp-connecting tabs to the powersupply through associated similar sockets.

Another object of our invention is to provide a socket for an electriclamp comprising tabs for connectively-receiving contact elements of saidlamp, with leads extending from said tabs for connection throughassociated similar sockets to a source of power, and material which isnormally substantially non-conducting, but will break down and conductwhen the voltage is increased a predetermined extent and again revert tosubstantially non-conducting condition when the voltage is reduced,disposed between said leads, whereby the voltage across the socket withthe lamp removed is approximately the same as with the lamp in thesocket, and a substantial proportion of the lamps may be removed and thestring relighted if the line voltage is removed, while more than onehalf of the lamps in the string may be removed While leaving theremainder still burning.

Other objects and advantages of the invention, relating to theparticular arrangement and construction of the various parts, willbecome apparent as the description proceeds.

Referring to the scale drawing:

Figure 1 is a. fragmentary elevational view, approximately full size inthe drawing accompanying this application, of a string of lampsinvolving one embodiment of our invention, and which may be used fordecorating a Christmas tree.

Figure 2 is an axial sectional View on a larger scale of one of thesockets of said string with a fragmentary portion of a lamp in place.

Figure 3 is a transverse sectional view of the socket, on the lineIII-Ill. of Figure 2, in the direction of the arrows.

Figure 4 is a transverse sectional view on the line IVIV of Figure 2'.

Figure 5 is a perspective view of one of the lamp contact receivingtabs, separated from its socket.

Figure 6 is a fragmentary axial sectional view,

corresponding to Figure 2 but showing a modification.

Figure '7 is a transverse sectional view on the line VIIVII of Figure 6,in the direction of the arrows.

Figure 8 is an axial sectional view on the line VIII-VIII of Figure '7,in the direction of the arrows.

Figure 9 is a view corresponding to Figure 2, but showing anothermodification.

Referring to the drawing in detail, and first considering the embodimentof our invention illustrated in Figures 1 to 5, inclusive, there isshown a string or series of sockets all formed as designated at H, H ll(in Figure 9) N or H or some formed one way and others another way orother ways, which may hold lamps adapted to operate on 5.9 volts with acurrent of .22 ampere, as specifically disclosed as a preferredembodiment in the Way application subsequently referred to, forChristmas tree decoration or other purposes, receiving power through acontact plug l2 and lines I3 and M from an electrical utility outlet IE,or other source of power. Each socket may be as shown in detail inFigures 2 to 5, inclusive, that is, it may consist of a hollowcylindrical element or sleeve l6 of paper or other insulating material,in which is mounted an insulating plug member [1 or one formed with apair of apertures l8 and I9 extending therethrough. The inner ends ofthe apertures, cavities or pockets l8 and 9 are restricted, as indicatedat 45 and 41, and countersunk at 48 and 49 to guidingly receive thecontact elements or prongs 25 and 26 of lamp 21.

In each of the apertures I8 and I9 is disposed a tab or lamp contactgripping element 2|, constructed as shown in detail in Figure 5. In thepresent embodiment, each tab 2| is formed of spring metal and has a wellor pocket 22 between resilient gripping elements 23 and 24 thereof. Oneof theconducting prongs or projecting lead members 25 and 26 of anassociatedlamp 27, may be gripped between the elements 23 and 24, asshown most clearly in Figure 2. Each tab 2| also comprises a conductiveflattened extension or tail 28 which may be imperforate, or apertured asindicated at 29 and/or 3|. Between a pair of said extensions 28 lyinggenerally parallel in each socket, is disposed a quantity of material32, the partition 33 between the apertures I8 and Hi being partially cutaway for the reception of said material, as shown most clearly in Figure2.

The material 32 may be of a type which is substantially non-conductingunder normal operating conditions, but will break down and conduct whenthe voltage is substantially increased above the normal voltage, andagain revert to a substantially non-conductive Condition when thevoltage is reduced. A predetermined breakdown voltage starts across thematerial an are which holds until the voltage approaches zero. It isalso of such construction that after breakdown it has sufficientresistance to cause a voltage drop approximating that of the lamp,thereby preven ing abnormal current from flowing in the remaining lampsof the string.

Material for such purposes desirably consists of one selected from thegroup consisting of manganese, manganese oxide, and compounds ofmanganese and silicon, which have the proper conductivity for use in thesockets for six volt lamps, adapted for a supply voltage of about 120with 20 in a string, and silicon or silicon carbide if lamps of highervoltage are to be used. One preferred formula is to take manganese of 20to 30 mesh which has been slightly preoxidized and moistened with abinder, selected from the group consisting of plaster of Paris andsodium silicate, to make a slurry which is run in between the pair ofextensions 28 and, at the same time, performs the additional function ofcementing such tabs in the socket plug [1.

It has been discovered that particles of manganese may have a highcurrent passed therethrough to fix the amount of oxide at the pointswhere the crystals engage one another, thereby fixing the voltagebreakdown and conductivity. Such a mass, especially when the particlesare fixed in relation with respect to one another, as by making a slurrysuch as previously described, has a given breakdown voltage while, atthe same time, it will revert to a substantially non-conductingcondition when the voltage is reduced sufficiently. The predeterminedbreakdown voltage starts an arc across the oxidized material, which areholds until the voltage approaches zero. After the material 32 has beenplaced, as indicated in Figure 2, the lower end of the socket may beclosed by a cap 34. If such sockets are to be used for Christmas treelighting, a bead 35 may surround the leads 36 and 31,, which extendthrough the cap 34 and have their ends crimped to the gripping elements23 and 24, as indicated at 38 and 39, or otherwise electricallyconnected thereto. The cap 34 may be held in place in any desired manneras by cementing, or formed in accordance with one of the succeedingembodiments to be described.

The lamp 2'! which is preferably used in the socket described, may havea filament ll mounted on the inner ends of leads 42 and 43, which may beof relatively small section and project from the relatively largecontact pins. The points of union between the leads and pins aredesirably imbedded in a relatively flat press 44, which with the prongs25 and 26, function as the base. The lamp is sealed, after exhaustionand/or gas filling, at the tip 45. A preferred form of lamp is describedand claimed in the Way application, Serial No. 748,779, filed of evendate herewith, now Patent No. 2,491,237, dated December 13,

Referring now to the embodiment of my invention illustrated in Figures6, 7, and 8, there is shown a socket I I which may replace the socketsof the string illustrated in Figure l, or be used interchangeably withone or several of said sockets, as illustrated in Figure 1 by the factthat said sockets are of non-uniform appearance and differentlydesignated. In the present embodiment, the socket I I is formed ofplastic such as an insulating thermosetting resin of the condensingtype, examples of which are phenolformaldehyde, furfural andurea-formaldehyde, and the interior portion ['1 is integral with theouter generally cylindrical portion W In other words, the completesocket casing, Hi -Il may have a pair of apertures it and w extendingtherethrough and restricted at the inner ends, as indicated at 46 and 51The restricted apertures lli and ll are countersunk as indicated at 48and 49 to guidingly receive the contact elements 25 and 26 of anassociated lamp 27. In the present embodiment, each tab or lamp contactgripping element Zi is relatively short, but its resilient grippingelement portions 23 and 24 may correspond with those designated 23 and24 in Figure 5. However, instead of each having a relatively longconductive extension 28 as in Figure 5, the extension 28 in the presentembodiment is relatively short, and the corresponding lead 36 or 37 asthe case may be, is flattened as indicated at 5| and 52 and bent to beoffset, as indicated at 53 and 54. The flattened offset portions extendparallel, like the extensions 28 in the preceding embodiment, beingconnected to the relatively short portions 28 of the tabs Zi as bysoldering or welding indicated at 55 and 56. The partition 33 betweenthe apertures i8 and ll-i is cut away along said flattened portions 5|and 52 and filled with a quantity of material 32 which may correspondwith the material 32 of the preceding embodiment.

In the present embodiment, however, the socket portion 16*, by virtue ofits construction, may be more ornate than that of the socket 15 of thepreceding embodiment, in that it may be molded to the outside appearanceillustrated in Figure 1. That is, it may represent wax portions 51dripping from the top edge, as if it were a candle, and the lamp 2! theflame. Or it may be formed with the lower bead or flange portion 58omitted, so as to have an appearance as represented by the referencecharacter l l in Figure 1. After the material 32 has been placed asindicated in Figures 6 and 7, the lower end of the socket may be closedby a cap 3%, which may be preformed with a bead 59 cooperating with acorresponding groove 6!, sothat it will snap into place and hold theparts in the position illustrated in Figures 6 and 8.

Referring now to the embodiment illustrated in Figure 9, a constructionis there disclosed which may be identical with Figures 6, 7 and 8insofar as the casing [6 of the socket li is concerned. However, in thepresent embodiment the tabs 2 1 are like the tabs 2 l of the firstembodiment, except that the portions 23 and 24 forming pockets 22thereof are not crimped about the leads 36 and 31 said leads insteadbeing passed through apertures 2.) and then back through apertures 28 asillustrated, so as to provide a tighter connection between the leads andtabs. Otherwise the construction of the socket may correspond with thatof Figures 6, 7 and 8, as it may have a closure. cap

like that designated 34*, and be formed for reception thereof as in thepreceding embodiment. As an alternative, however, a cap 34 asillustrated, may be employed and held in place as by a lock spring 62fitting in a corresponding groove 63.

It will also be understood that in both the form of Figures 6, 7 and 8and that of Figure 9, the top or cup-shaped portion of each socket isdesirably formed, not only for the guidance of the pins 25 and 26 bycountersinking at 48* and 49, or 48 and 49*, as the case may be, butalso tapered as indicated at 63, and formed with a narrow fiattenedsection indicated at 64, so as to provide a guiding pocket correspondingwith the shape of the base, or flattened pressed portion 44 of the lamp21.

Although preferred embodiments of our invention have been disclosed, itwill be understood that modifications may be made within the spirit andscope of the appended claims, and that we contemplate transposition offeatures. For example, any one of the forms of caps 34, 34 and 34*, maybe used with any form of socket. Although we have shown lampsparticularly adapted for use in a Christmas tree string, we do not wishto be limited to this showing. Such sockets may be used where lamps forseries operation are desired, unless the voltage is not suitable for theshort circuiting material disclosed. Said material, however, may bevaried to accommodate different voltages.

We claim:

1. A socket for an electric lamp having contact elements, comprisingtabs for connectively receiving said contact elements, leads extendingfrom said tabs for connection to a source of power, and material whichis normally substantially nonconducting disposed between said leadsadjacent said tabs, said material consisting of preoxidized 20-30 meshmanganese, moistened with a binder selected from the group consisting ofwater-admixed plaster of Paris and sodium silicate solution to form aslurry, and cementing said tabs in the socket.

2. A socket for an electric lamp comprising an outer generallycylindrical portion, an internal portion formed with a pair of parallelapertures terminating in restrictions flared to guidingly receivecontact prongs of an associated lamp, a contact tab disposed in eachaperture and each tab consisting of a lamp contact prong grippingportion normally underlying a restriction and a conductive tail portionprojecting toward the outer end of its receiving aperture, and materialselected from the group consisting of manganese, manganese oxide, andcompounds of manganese and silicon, which has the proper conductivityfor a six-volt lamp so that it will break down and conduct electricitywithin a substantially higher range of voltage, and again revert to asubstantially non-conductive condition when the voltage is reduced, saidmaterial being moistened with a binder selected from the groupconsisting of water-admixed plaster of Paris and sodium silicatesolution to form a slurry, and cementing said tail portions in saidsocket, whereby the voltage across the socket when operating in a stringand when the lamp is removed is approximately the same as with the lampin the socket, because of said cementing material between said tailportions.

CLAIR MICHAEL RIVELY. HENRY W. RIMBACI-I.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 319,177 Bernstein June 2, 1885456,327 Smith July 21, 1891 481,019 Ford Aug. 16, 1892 625,395 Houstonet a1 Feb. 23, 1899 1,024,495 Booth Apr. 30, 1912 1,491,340 Curtis Apr.22, 1924 1,745,690 Pritchett Feb. 4, 1930 1,954,355 Handy Apr. 10, 19342,332,077 Hays -1 Oct. 19, 1934 2,072,337 Kamm Mar. 2, 1937 2,177,806Kamm Oct. 31, 1939 2,408,124 Rolfes Sept. 24, 1946 2,431,151 TellegenNov. 18, 1947 FOREIGN PATENTS Number Country Date 288,988 Germany Aug.15, 1914

